240z SCCA vintage race car, restoration

[AydinZ71]

So unfortunately, the person I sold my street car to for 5yrs put flares on there, so I can’t compare. But what I can do is compare to the other side of the car which does not have any patches. 
 

i think I just need to know what it’s “supposed” to look like and everything will fall  into place. It just seems like the extreme ends of the flare go beyond the wheel arch. They seem to wander further onto the body vs. staying right-over the OEM lip. This might be 100% as designed. 

Edited August 9, 2022 by AydinZ71

[AydinZ71]

PS: 100% agree on hammer-dolly the body. Epoxy is on there as over-spray during the sealing of my roof and prep for filler on the hatch area. Reason why I have not done-so is I want to cut the OEM wheel flare/lip before I finish my metalwork. If I hammer everything out and cutting the arch warps the body because of static stress it would be a waste. 

 

Hence getting the fitment on the flares now is the next-step to finish the metal work in this area, including drilling the mounting holes. 

[Dat73z]

Yes you do see the fender lips a bit on the bottom like that. I think you have them close enough where I'd say position where you think it looks right and go for it. 

 

When you trim the fenders, leave the bottom portions alone such that when you look at the car from various angles it'll retain the stock body lines at those lower areas. 

 

If I can find some pictures I'll send them to you

[AydinZ71]

Thanks for your help @Dat73z!

 

Hopefully I did it right! The ride height it set way high right now. It should look right once it’s lowered a few inches. 
 

5/16 rivnuts. I plan to use weatherstripping to make a flush-fit. I really don’t mind the black accent on the edge of the flare, but I know many do. 

[Dat73z]

That looks really good @AydinZ71. Looking forward to seeing the bodywork finished 👍

[AydinZ71]

Well folks, two years-in and I’m still a fraud as a race car driver but apparently I can add bodywork to the list, haha. 
 

rear passenger quarter panel bodywork is done and sealed (epoxy). Working my way around the car, but also started back up on the fenders. Need to get them ready for sealer as the surface rust just marches-along. 
 

As much as I love the closed headlight covers, it won’t meet EP so I got started on fitment/clearances on the OEM steel bezels. Decided to just weld the bezels in, and remove any unnecessary steel in the process. Still using that thin-wall SS tubing where I can for it’s rigidity and light weight. Got the velocity stack mounted on the drivers side. I put quite a bit of pressure on it, and doesn’t seem to be going anywhere. I cut a narrow ring of 3” 16-gauge tube, split the ring, welded on a standard worm drive hose clamp, and used the thin SS tube as a cantilevered mount. 
 

Question for you real race car drivers: what are your thoughts on sealing the space between the velo stack and the headlight bezel? Is there a particular aero reason you would want to limit the amount of air leaking into your fender? I’ll be honest, I can’t tell if allowing a leak path for the high-pressure air here is a good or bad thing. @JMortensen @jhm. @tube80z @clarkspeed

Edited September 2, 2022 by AydinZ71

[JMortensen]

Sealing everything up tight would be the goal, but in practice I don't think you're going to see a whole hell of a lot of difference one way or the other. I'd put a piece of sheet across the opening and fasten to the fender or bucket, and then cut the hole in the middle for the scoop. Sometimes I do these "simple" things and then hours into it I realize that it was a waste of time, then I have to do the sunk cost fallacy appraisal and decide to finish or cut my losses. Your mileage probably won't vary too much. ;)

[AydinZ71]

Thanks Jon! I actually have quite a bit of different styles of weather-stripping I can try. I bought a bunch off mcmaster to try them out on the rear hatch area and fender flares. Otherwise, the sheet metal ring around the OD of the velo stack is a definite solution!

 

Why I brought this up: I noticed the new Le Mans rules require a huge hole in the fender to allow pressure to be relieved in the wheel well. Apparently they feel the massive pressure imbalance between the wheel-well and the air traveling overhead was a contributing factor in seeing those cars "fly" ( you have probably seen the famous vid of the Mercedes flipping backwards on the straight). That's my first indication that air flow (or lack of) through the fender cavity is a consideration. 

 

Aero stuff is not always intuitive, so I thought I would learn from you actual racers! Doubt the EP car will get much over 130mph, so I may be over-thinking as usual. 

Edited September 2, 2022 by AydinZ71

[JMortensen]

Z's taking flight is not something I worry about, but also the last time my Z was on a road course was 2002 and it probably topped out at 120ish with the triples and the L28. Many people more worth of the title "racer" than me. Unfortunately I spent way too much time building and way too little time driving, and it's been all autox for the last 20 years. Hopefully I'll fix the shop/driving ratio in the next couple years.

[AydinZ71]

19 minutes ago, JMortensen said:

Z's taking flight is not something I worry about, but also the last time my Z was on a road course was 2002 and it probably topped out at 120ish with the triples and the L28. Many people more worth of the title "racer" than me. Unfortunately I spent way too much time building and way too little time driving, and it's been all autox for the last 20 years. Hopefully I'll fix the shop/driving ratio in the next couple years.

 

Haha! Can you imagine a flying Z? Better be a G-nose. I wasn't worried about lift-off, but rather a loss of down-force on the front wheels or increase in Cd. 

 

Honestly since my credential at this point is limited to "fabricator", I still want to build a competitive car just to satiate my over-achieving (more like obsessive) nature.  It sounds like I have much bigger worries than some air getting into the wheel well. 

 

I got the 130mph figure watching Greg's races. The highest I saw on his digital dash PIP was 136, and that was at Road America's straight. He was running a read-deal EP motor though, @260hp & 2150 lbs including driver. 

[tube80z]

My advice is to keep high-pressure air out of the underside of any surface.  That's why you often ducting the front radiator adds so much downforce compared to a lot of other mods.  In the fender example I'd do what Jon said and flat plate the back of the light bucket and use that as your air scoop.  Then run a replica inner wheel liner and call it good.  I don't think EP offers enough scope to allow for s-flaps or doing an inner bucket style liner.

 

Cary

[AydinZ71]

5 hours ago, tube80z said:

My advice is to keep high-pressure air out of the underside of any surface.  That's why you often ducting the front radiator adds so much downforce compared to a lot of other mods.  In the fender example I'd do what Jon said and flat plate the back of the light bucket and use that as your air scoop.  Then run a replica inner wheel liner and call it good.  I don't think EP offers enough scope to allow for s-flaps or doing an inner bucket style liner.

 

Cary

 

Thanks Cary! Indeed, pretty limited in EP. I kinda like it though, keeps me from going off-the-rails with too many crazy ideas until I can get some actual track experience (whenever that will be). Il keep going  

 

I decided to give the Skillard air dam and splitter combo a try. Speaking with them, I may be the first person trying it out on a (hopefully) competitive car. I have some aero changes in mind, but the biggest seller for me was the splitter already ends where my EP rules require it to. I think I could have fabricated something similar, but I’m really trying to stop the immediate inclination to fabricate everything. My read of the GRC makes it acceptable, as it does not depart from the overall “envelope” of the car. Hood remains the furthest-forward body panel. It’s also lower than the conventional fiberglass/urethane units so I may not need a front-end scraper like Greg had. 

[AydinZ71]

Hi all! It has been a while. I was in Europe for two weeks, than had COVID which knocked me out for another two weeks. Finally getting back to the car. 

 

For competition, I have a button flywheel/clutch combo from quartermaster sitting on my shelf. They wear pretty quick if you are doing any street driving or stop/go. I'm looking for a clutch I can use for off-competition tuning and getting it to and from places. Will also use it for track days until I get the suspension tuned. I have a Kameari 9lb flywheel in the OEM formfactor I plan to use. 

 

I was going to just default to an inexpensive OEM spec Exedy clutch, but was curious if ya'll had any recommendations. I steer-clear of all the BS clutches that are marketed at "stages". In the past I would order custom clutches with un-sprung disks and dual diaphragm pressure plates (my L28et), but the shop has since gone out of business. 

 

The L24 as built today wont put out more than 160-170ft-lbs, so not much need for grip. 

[tube80z]

On your button clutch are you using the rally disks?  I converted my 3-disk quartertilton (yes mix and match parts) to a 2-disk rally version.  We have a local CP guy using one behind a 377 LS with a dog box and he's been driving on it for a year and a half at autocrosses and hillclimbs.  I think Jon may have a similar setup or perhaps the grabbier metallic disk version. 

[JMortensen]

Mine is a standard dual 7.25 with the sintered iron disks. It's grabby, but it works great. Car shifts amazingly fast, and it's a T56 which are notorious for not shifting very well.

[AydinZ71]

17 hours ago, tube80z said:

On your button clutch are you using the rally disks?  I converted my 3-disk quartertilton (yes mix and match parts) to a 2-disk rally version.  We have a local CP guy using one behind a 377 LS with a dog box and he's been driving on it for a year and a half at autocrosses and hillclimbs.  I think Jon may have a similar setup or perhaps the grabbier metallic disk version. 

 

13 hours ago, JMortensen said:

Mine is a standard dual 7.25 with the sintered iron disks. It's grabby, but it works great. Car shifts amazingly fast, and it's a T56 which are notorious for not shifting very well.

 

It is a 5.5" with two disks. True story, I told Greg Ira I planned to run the 9lb flywheel and asked for his advice on a clutch. He laughed at me, and said "you are kidding, right?" and shipped me his identical spec (he just added +qty 1 to his order). I want to say it was around $1200. I could ask him the details, but I think he was pretty protective (at the time) about disclosing too much. As he said to me "you know how long it took me to settle on this setup?". On-track he said it would last two seasons as long as you are rev-matching and baby-it in first gear.

[JMortensen]

You probably already know this but just FYI, "baby it" means DO NOT let it slip. I will let the clutch out part way, quickly, to kind of lurch the car forward when I'm sitting in line at an autox. Don't be gentle. Gentle = bad.

Edited October 19, 2022 by JMortensen

[tube80z]

4 hours ago, AydinZ71 said:

 

 

It is a 5.5" with two disks. True story, I told Greg Ira I planned to run the 9lb flywheel and asked for his advice on a clutch. He laughed at me, and said "you are kidding, right?" and shipped me his identical spec (he just added +qty 1 to his order). I want to say it was around $1200. I could ask him the details, but I think he was pretty protective (at the time) about disclosing too much. As he said to me "you know how long it took me to settle on this setup?". On-track he said it would last two seasons as long as you are rev-matching and baby-it in first gear.

 

My friend has an EP car and they raced a dual-disk Tilton all year and we measured the disks and floaters after a couple of events and they had hardly any wear.  It raced all year and had some wear on the floaters but was still in spec to be used.  He then moved to a 4.75 triple disk.  It's really cool to hear an L6 rev like a superbike.  

 

The EP car did have a dog box in case that matters and it's driven like Jon mentions using small stabs to get moving from a stand still.  Quickest way to kill it is try and drive it into the trailer.  I've seen that done a few times.  

[AydinZ71]

3 hours ago, JMortensen said:

You probably already know this but just FYI, "baby it" means DO NOT let it slip. I will let the clutch out part way, quickly, to kind of lurch the car forward when I'm sitting in line at an autox. Don't be gentle. Gentle = bad.

 

1 hour ago, tube80z said:

 

My friend has an EP car and they raced a dual-disk Tilton all year and we measured the disks and floaters after a couple of events and they had hardly any wear.  It raced all year and had some wear on the floaters but was still in spec to be used.  He then moved to a 4.75 triple disk.  It's really cool to hear an L6 rev like a superbike.  

 

The EP car did have a dog box in case that matters and it's driven like Jon mentions using small stabs to get moving from a stand still.  Quickest way to kill it is try and drive it into the trailer.  I've seen that done a few times.  

 

Yep! Greg basically told me not to slip the clutch if I could help it. With that said, don't drop it at high rpm either. 

Like you said Jon, short engagements at low RPM just to get it rolling. 

When you think about it, there really isn't a means for the clutch to wear if you are rev-matching and out of first gear. Its slipping just enough to absorb the drivetrain shock between gear changes, and no more. 

 

4.75"! That is wild!! Heck if you can get by push-starting it, you don't even need the auto-trans ring gear either! 

 

Ok, unrelated (you said rev like a super bike) but I am super excited to get my Kameari rods for the 3.1L (not EP)! They are stuck in customs up in Alaska, but I already have the forged pistons in-hand. They were the lightest set of pistons/rods with the largest rod ratio of any manufacturer I could find, short of commissioning something completely custom. This engine is two years in the making. 

[clarkspeed]

I have found the toughest thing on a 5.5 and smaller button clutch is pulling it on a trailer. Many winch just for that reason. I also found the 7.25" dual clutch set up to be much more forgiving. Virtually same durability and heat resistant as a stock based setup. Can work for street or track.